This invention relates to the mechanical, electrical, magnetic or other mechanized recording and reproduction of auditory and/or visual or other data, and particularly to improvements to a process of recording which enables human users to decide whether to preserve a record of events that have already transpired.
My earlier patent, U.S. Pat. No. 5,845,240 (Selective Recall and Preservation of Continuously Recorded Data), discloses a recording method that effectively allows a user to decide to record an event after the event has taken place. This is achieved by continuously recording all ambient events in a continuous logical loop on a finite extent of recording medium and allowing users to select for permanent preservation portions of the material thus recorded, before they are overwritten with new material.
The present invention comprises improvements to and applications of this basic technology.
One area of technology addressed by the present invention is event-activated recording, in which a recording process is initiated on the occurrence of some event that is recognized by some mechanism, algorithm or other automated means. Current examples include:
(1) Voice-activated recording of speech
(2) Sound-activated recording of sound
(3) In a security system, audio and/or video recording activated on detection of movement
(4) In a medical instrument, recording initiated by some significant event, e.g., an arrythmia
A drawback common to all of these methods is the fact that they do not record the often-significant events leading up to the event that triggers the recording process. (Indeed, because some time elapses between the occurrence of the triggering event, detection of the event, processing of the resulting signal, recognition of the event as significant, and finally initiation of the recording process, the triggering event is usually not recorded, or only partially recorded.)
The present invention overcomes this drawback by providing an acquisition buffer (of a rewritable recording medium) in which current events are continuously recorded. When the recording process fills the acquisition buffer, it overwrites the record of the earliest events recorded in the buffer with current events. On detection of a triggering event, a predetermined portion of the current contents of the acquisition buffer (which may be the buffer""s entire contents, or may correspond to a time interval that a user may specify) is transferred to the (permanent) recording medium normally used for event-activated recording. This has the effect of permanently preserving the events leading up to the triggering event.
A further area of application of the present invention is telephony. Current methods of recording telephone conversations share the drawbacks of conventional methods of recording: a recording process must be initiated (and, when applicable, consented to by parties to the conversation) before any of the events to be recorded have transpired.
Accordingly, it is an objective of the present invention to enable the effective recording of portions of a telephone conversation after those portions have taken place. It is a further objective of the present invention to secure the consent of parties to the conversation as a condition of such recording.
It is a further objective of the present invention to enable the recording of different kinds of data on interchangeable media such as flash memory.
Portable recording devices constitute a further area of application of the present invention. Current portable recording devices share the drawbacks of conventional methods of recording: a recording process must be initiated before any of the events to be recorded have transpired. The present invention is embodies in two devices that overcome these drawbacks: a pocket device and a wrist recorder, both advantageously using interchangeable media such as flash memory.
The present invention differs enables users effectively to record words that have already been spoken, or events that have already taken place, prior to the time that a user decides to record them. This is achieved by recording events on a finite extent of recording medium in a continuous logical loop (i.e., overwriting the earliest recorded data with new data whenever the end of the medium used for this continuous recording is reached), and playing back and/or permanently preserving (capturing) portions of the recorded data as selected by the user.
A further advantage of this invention is that it allows users to preserve the spontaneity of their speech and actions by dispelling the self-consciousness that sets in when people know that they are being recorded-which happens even when people record themselves, triggered by the very act of switching on a recording device. Moreover: Even in continuous monitoring methods, where continuous recording on an indeterminate supply of recording medium is practicable, there is the need to go back to search for and edit out the parts to be preserved, discarding the rest. The present invention goes far towards eliminating that need, by capturing data permanently only in response to a user""s explicit request (although this request must come within a predetermined, finite period from the time of the event).
The present invention may be applied to sound or video recording, as well as recording
(1) the sequence of user actions (or other events) on a computer or other machine or on a musical instrument,
(2) streams of data produced by medical or weather instruments, or
(3) streams of data produced by any broadcasting means, including xe2x80x9cnetcastingxe2x80x9d over the Internet.
The invention may be embodied, with varying degrees of practicality, using any rewritable recording medium, including electronic memory, tape, wire, or discs, both analog and digital. However, the current preferred medium for continuous recording is digital memory, as it entails a minimum of wear, power consumption and bulkxe2x80x94especially important in a portable device.
The essential components of this inventionxe2x80x94beyond a minimum of appropriate hardware to detect, acquire and preserve dataxe2x80x94are algorithms, which may be implemented as either hardware or software or both. The invention may be implemented as a program on a general-purpose computer, using either a single-thread or a multithreaded operating system, as long as means of acquiring and playing back data are provided.
Following is a description of an embodiment of this invention as a computer type program to capture audio data, running on an interrupt-driven computer of known type and using digital memory as the continuous recording medium. The same scheme may be used in a dedicated device other than a general-purpose computer; and variations of this scheme may be used to record other streams of events, e.g., video data. In this last case, the division of the continuous recording into blocks separated by intervals of silence may be replaced by a separation into blocks each having the same base frame as detected by a video compression algorithm.
This embodiment uses, in place of a single circular acquisition buffer for storing continuously recorded data, a circular array of smaller, separately allocated buffers. This arrangement affords a number of advantages on the design as compared with a single, larger buffer: (1) On general purpose computers, smaller blocks of memory are easier to allocate and move than larger ones; (2) smaller-size numbers (e.g., 16 bits for a 64 KB buffer) may be used to keep track of locations in the smaller buffers; and (3) this arrangement allows a simplified scheme for keeping track of areas that have been overwritten with fresh data.